The present invention relates to the field of aeronautical propulsion and, more particularly, to the field of high bypass ratio dual-flow jet engines, or turbofans.
Modern turbomachines conventionally take the form of an assembly of modules which may comprise stationary and moving parts. A module is defined as a subassembly of a turbomachine having geometric features at the level of its interfaces with the adjacent modules, which features are sufficiently precise for the subassembly to be delivered individually, and having undergone an individual balancing when it comprises rotating parts. Assembling the modules makes it possible to build up a complete engine, by reducing as far as possible the operations of balancing and pairing the interfacing parts.
Current turbofans comprise a plurality of compressor stages, in particular a low-pressure (LP) compressor and a high-pressure (HP) compressor which form part of the primary body of the engine. A large wheel of moving blades, also known as the fan, is located upstream of the low-pressure compressor. This fan supplies both the primary flow, which passes through the LP and HP compressors, and the cold flow—also known as the secondary flow—which is immediately directed toward a cold flow duct known as the secondary duct. The fan is driven by the rotating shaft of the LP spool and generally rotates at the same speed as the latter. It can, however, be of interest to make the fan rotate more slowly than the LP shaft, especially when the fan is very large, in order to achieve better aerodynamic design. To this end, a reduction gear is arranged between the LP shaft and a fan shaft bearing the fan. The fan, the fan shaft and the reduction gear generally form one module, called the fan module.